Twitter allow title to just beAuthor only

[ricklahaye]

Hi.

Twitter does not use any titles, so RSSHUB uses description as a title. I would like to see that we can set the Title to just the author only. Its possible to include the title already with showAuthorInTitle, but I would propose to also add showAuthorInTitleOnly to force the title to only include the author, and not the description.

This change shouldn't be hard.

        if (showAuthorInTitleOnly) {
            title == originalItem.user.name
        }

[ricklahaye]

Implemented in #17673